A magnetron is a device that may be installed in a microwave oven, lighting device, and the like, and that may convert electric energy into high-frequency energy such as a microwave.
The magnetron may output, based on oscillation, electromagnetic waves with high frequencies, for example, at a 2.45 GHz fundamental frequency, and may generate harmonic frequencies, for example, at frequencies twice, three times, . . . , N times of the fundamental frequency, where N represents natural numbers.
In some cases, a magnetron may operate with methods for shielding (removing or minimizing) harmonic frequencies as well as the fundamental frequency.
For example, a magnetron may include four chokes in an output unit thereof that may shield second, third, fourth and fifth harmonic frequencies with a high level of noise intensity (intensity of harmonic frequencies).
FIG. 1 is a sectional view of a magnetron including four chokes in related art.
As shown in FIG. 1, the magnetron may include four chokes (CK2, CK3, CK4, and CK5), and the second to fifth harmonic frequency chokes (CK2 to CK5) may shield second to fifth harmonic frequencies respectively.
In some cases, a short circuit or a spark may occur in the second-harmonic-frequency choke (CK2) due to a short distance between the second-harmonic-frequency choke (CK2) and an antenna feeder (AF). The short circuit may be related to the electromagnetic structure.
In some cases. the chokes may be lengthened to improve the function of shielding harmonic frequencies. In some cases, a second-harmonic-frequency choke (CK2) may be limited in lengthening due to the interference between an antenna feeder (AF) and the second-harmonic-frequency choke (CK2).
In some case, the harmonic shielding performance of a second-harmonic-frequency choke (CK2) may be worse that of the other harmonic frequency chokes (third to fifth harmonic frequency chokes (CK3, CK4, and CK5)).